Hi everybody,I've been building a LED headlamp in my free time, the result is on my GitHub. This version has quite a lot of disadvantages that should be removed in next iteration. As I need to pick my university bachelor project soon, I decided to improve the current design.

What would be your ideal headlamp? What parameters do you require, what light modes, controls,...

So far I've got a list of ideas:- two LEDs (spot and flood), most likely Cree XM-L2, with separated brightness control- switching buck convertor with high efficiency (one of the key part of the thesis - I need something "science" looking )- aluminium body (alloy 6082 with colored anodized finish), not sure about the shape, cylinder like Scurion, or something closer to rectangle?- controlled by knob rotation - easy to make it waterproof, two buttons => easier to operate than single switch- battery level indicated every 10% of discharged capacity by blinking one of the leds, when charge goes below like 30%, dropping maximal light output to lower level, etc- very low power mode - around 10 lumens, no need to burn battery when digging in a cave or crawling in a tight space- autonomous mode when output power is determined by amount of reflected light - low when looking into map, digging, crawling,... high when looking into big cave hall (a bit of overengineering but hey, it's a bachelor project, it has to contain some science )- mounting compatible with gopro holders- Leds should be easily replaceable, e.g. just connected by two wires to motherboard, right now, swapping LED requires small heating gun and bit more soldering skills...- maybe a small red LED for better eye adaptation to the darkness - astronomy, etc,...- should be able to run on a single 18650 LiIon cell, even when going flat, it shouldn't just turn off, better dim than no light- maybe a bit warmer color temperature, it feels much better than cold white for me- some kind of user programming mode, preferably from PC/smartphone (let's make it morecomplicated to make the teacher happy...), basically anything should be changeable - light modes, button functions,... + some statistics could be shown - time spent in different modes, most and leas used mode,...- shouldn't be much heavier/bigger than the current version

If this is just a gimmicky university waste-of-time "science" project, then it doesn't much matter what the ideal headlamp is. Give your light wheels and fangs and a fold-away, 3-peice, silicon kitchen utensil kit.

If you want to know the commercial ideal, the answer will always be smaller, brighter and tougher, with better runtime. The thrill of fancy features will wear off more or less immediately, leaving users face to face with the basic quality of the thing. Compare specs to the lights currently available. Can you improve on those?

It's not supposed to be a waste-of-time project, the current version was build in my free time for fun, it still has many disadvantages and as I don't want to do any of the project offered by university (way too academic and useless in normal life), I decided to improve something I use. And if I must do something, I want to do it properly, there's no reason to build something and put it into drawer forever after the project is finished. I was thinking about other projects (e.g. robotic astronomy telescope), but they are either too easy or quite a long term, therefore the headlamp.

It's not easy to fight with companies developing lights for decades, it might be smaller, but not brighter or longer lasting (most likely, who knows).

I've been to caves few times and I definitely want to start caving much more often, currently I use the headlamp mostly for cycling, rock climbing and camping.

I'm asking here because lightsource is your most important equipment, so you are the best source of knowledge. I've already spend significant amount of time browsing various headlamp on the internet, but what I need is feedback from people who use them very often.

What you hate on your lamp? What you love? Do you prefer single button or rotation knob for controls? Single LED or two independently controlled? Do you prefer changing modes by the controls or is it better to step output power independently for each led? Do you like petzl reactive lighting technology? Etc... That's the kind of informations I need.

Btw, the project will be released under opensource license once it's finished.

kajus wrote:What you hate on your lamp? What you love? Do you prefer single button or rotation knob for controls? Single LED or two independently controlled? Do you prefer changing modes by the controls or is it better to step output power independently for each led? Do you like petzl reactive lighting technology? Etc... That's the kind of informations I need.

Alright. I use Zebralights of various models. I like that they are bright, simple, small, and so far, durable. Check out their site for specs. Button/knob? I prefer whatever is most streamlined and durable. If it sticks out it will more likely break, especially under abuse by cavers. Reactive lighting sounds like a gimmick and at any rate would probably be the first thing to malfunction.

What cavers need the most from lamps is for lots of light to reliably come out of a reasonably small package. Everything else is unimportant.

yup, Zebra lights. Sure you can spend hundreds of dollars for huge weighty aluminum discs on your head with all sorts of ways to program the light levels, but really you just want it to shine bright, maybe have two or three light levels, and have a replaceable battery. Ive had an ElSpeleo for years and I still use it as a video light or for light painting but Im not putting it back on my helmet. Its hard to beat the functionality, weight, light throw, and reliability of the Zebra.

But this is also because here in Montana its a hell of a long hike to most caves of note, so weight and reliability in the field are paramount. If I was living back in TAG maybe I would go for your light, turn it up all the way, and dry off the rocks and mud as I make my way through with the obscene number of lumens and heat I can throw out.

Or how about making a variable focus beam flashlight/ laser like from ring world? Light your way AND blast through rock all with the same device!

Good point on the button/knob, knob is used quite often (Rude nora, etc.) but it's a bit prone to breaking, buttons looks better, well at least if I find waterproof ones for reasonable price.

So you see no advantage on "reactive lighting"? I thought it's a nice way to save the battery life. Just set the highest and lowest light level you want to use and let the lamp take care of the rest, it's useless to output several hundred lumens when crawling in a narrow places or digging in the sediments. Just get closer to the rock and the power goes down automatically without need of covering the lamp in mud from your hands looking for the control button. Look into a big hall and power goes up to the limit you set before. Also it should reduce the problem when you run for a longer time on high mode and killing battery without realizing that.I do realize it's something a bit complicated that could break up, but it's easy to make this feature optional or turn it off by some key sequence. Simplicity is my goal, but it's a bit against the way universities work.

I do realize the hunt for highest light output for toasting bats and setting rocks on fire is nonsense, but two leds (wide and narrow beam) limited to about 50% of their power rating (to reduce heating and keep the efficiency reasonably high) sounded like a good idea to me. Focusing is nonsense, more mechanical stuff that could break up without many benefits.

Edit: What about the constant light output? Do you prefer running on the same light output the whole battery life and decreasing levels when battery goes flat, or is light output without regulation (light output drops during battery discharging) better for you?

I've followed the herd to Zebra, too. My biggest objection is that they require a "special" battery and not AA. Just about everything I own - from cameras to flashlights/headlamps to portable shaver -- runs on AA. You can get AAs anywhere in the world from Botswana to Bolivia, Boston to Bismark. My problem with non-AAs for cameras, etc. is that the chargers don't always work overseas, nor are charging outlets available. However, since most of my caving is domestic and most of my cave trips are under 14-16 hours anymore, having a Zebra and a charged backup battery has served me well. Just about every Micky D's or cafe in the USA has a plug where you can recharge stuff from cell phones to Zebra lights. I do, however, have a pair of Princeton Tec AA-powered headlamps as backup.

For charging 18650's overseas, my charger accepts 100-240V at 50 or 60 hz. That means I just have to get US plug to (insert country) plug adapter. I don't need to get a converter, just an adapter to change the shape of the plug. You can find this on the label for the charger. Since this is just an AC to DC converter this likely works with most chargers.

caver.adam wrote:For charging 18650's overseas, my charger accepts 100-240V at 50 or 60 hz. That means I just have to get US plug to (insert country) plug adapter. I don't need to get a converter, just an adapter to change the shape of the plug.

If it has the C7/C8 (aka Figure-8) connector you can also usually just get the appropriate cord. My chargers both have that option.

kajus wrote:Well that kind of headlamp would be nice, but radioisotope thermoelectric generator is quite bulky device to carry on your helmet,... Let's stick with batteries.